The invention concerns a pen or pencil comprising a shaft which in its peripheral surface has at least one first and at least one second surface region.
Pens or pencils of the kind set forth above are known. If such pens or pencils are to be individualized, the two surface regions referred to above serve for that purpose. More specifically, if they are suitably arranged and if they are optically different from each other, they can serve for individualization purposes. In that respect, it can not only be provided that for example the second surface region is in the form of script. On the contrary, it can also be in the form of a pattern such as for example longitudinal stripes (for example at longitudinal edges).
In the case of known pens or pencils, the second surface region is frequently formed by being raised or recessed with respect to the first surface region. That admittedly achieves an optical effect. Frequently however that optical effect is not sufficiently clear-cut and striking, so that it can be easily overlooked. Another option in regard to an optically different configuration as between the first and second surface regions provides that a shaft which is of a first color is covered in a portion-wise manner with a layer or coating of a second color, in order to form the second surface region. With that arrangement however problems arise in particular when the second surface region is raised with respect to the first surface region or is disposed for example in the region of the above-mentioned edges, because in that case the colored layer all too easily wears away in use.
An object of the present invention is to design a pen or pencil of the kind set forth in the opening part of this specification, in such a way that the second surface region can be optically easily distinguished from the first surface region, but nonetheless the risk of wearing away does not occur.
In accordance with the invention, the specified object is attained in that irradiation of the first surface region with light of a first light quantity per unit of surface area results in an emission of visible light in the second surface region (which is adjacent to the first surface region), wherein the light quantity emitted in the second surface region per unit of surface area for at least one first frequency is greater than the light quantity per unit of surface area of the first frequency, which is absorbed by the first surface region.
In other words, the light impinging on the second surface region is not simply reflected, as in the case of the coating of a different color for forming the second surface region, but that light which impinges on the first surface region is used for optical distinguishability of the second surface region.
As accordingly light is not (only) reflected in the second surface region but radiates out from the interior, the second surface region has a xe2x80x9cfluorescingxe2x80x9d action, whereby it can be optically readily distinguished from the first surface region.
As a coating which differs in color from the first surface region is not required for the second surface region, there is also no danger of it being worn away, more specifically not even if the second surface region should be raised with respect to the first surface region.
In principle, in accordance with the invention, it is possible to use any mechanisms in order to cause the second surface region to xe2x80x9clight upxe2x80x9din response to light shining on the first surface region. In accordance with the invention however it is preferred that the first surface region is the outside of a translucent part of the shaft, which includes a light-collecting substance, wherein the light-collecting substance receives the light shining on the first surface region and light emitted by the light-collecting substance issues from the shaft at least in part in the second surface region.
That design configuration is technically particularly simple to implement.
As already mentioned above, in accordance with the invention the shaft may have at least one longitudinal edge which at least partially coincides with the second surface region. In other words, in that way it is possible to provide a pen or pencil which has at least one xe2x80x9clighting-upxe2x80x9d longitudinal edge, wherein that lighting-up effect is maintained even if the edge should be knocked off.
In order further to protect the longitudinal edge and to increase the lighting-up effect, it can be provided in accordance with the invention that it is in the shape of a concave groove or channel.
In accordance with a particularly preferred embodiment of the invention the shaft, in regard to its cross-section, involves the outside contour of a polygon, the corners of the polygon each coinciding with a respective longitudinal edge. In other words, the invention in this embodiment provides a pen or pencil with a plurality of xe2x80x9clighting-upxe2x80x9dlongitudinal edges.
For the purposes of further simplification, it can be provided in accordance with the invention that at least one surface region of the shaft, which is between two longitudinal edges, does not coincide with the first surface region. In other words, in that configuration of the invention, light for the xe2x80x9clighting-upxe2x80x9d edge strips is not collected in each region between two edge strips. That can provide a saving in terms of production and material costs.
Thus it can be provided for example that the shaft has an even number of longitudinal edges and only each second surface region which is between two longitudinal edges coincides with the first surface region. Thereforexe2x80x94as viewed in the peripheral directionxe2x80x94light-absorbing and non-light-absorbing regions are disposed alternately. As however each longitudinal edge is adjacent to a light-absorbing region, each longitudinal edge can also be fed for xe2x80x9clighting upxe2x80x9d.
In accordance with an embodiment of the invention it is provided that the part of the shaft, which includes the light-collecting substance, extends as viewed in a radial direction over the entire thickness of the shaft. In other words, in this embodiment the shaft material is used in its entire depth for xe2x80x9cfeedingxe2x80x9d the second surface region.
As an alternative thereto, it can be provided that the part of the shaft which includes the light-collecting substance extends as viewed in the radial direction only over the outer 10%, preferably 5%, more preferably 2%, of the thickness of the shaft. This design configuration of the invention is based on the realization that the light-collecting substance has to be used only as far as a certain xe2x80x9cpenetration depthxe2x80x9d of the light for feeding the second surface region and thatxe2x80x94with the usual pen or pencil dimensionsxe2x80x94a comparatively small proportion of the total available shaft is already sufficient to adequately feed the second surface region.
In accordance with the invention the light-collecting substance is preferably Oracet Yellow 8GF (Solvent Yellow 145) and/or Oracet Pink RF (Pigment Red 181).
The shaft can be in the form of a sleeve or tube, the internal space of which serves as a storage means for the writing substance. In particular, when the shaft overall is transparent, it is possible to see the level of filling of the writing substance storage means, through the shaft. As the second surface regions are not formed by colored coatings, it is also possible to see unimpededly through them and it is therefore always reliably possible to see the level of filling of the storage means, even if the second surface region is comparatively large. It is expressly pointed out that the internal space of the sleeve or tube is considered as a storage means in accordance with the invention, even if it accommodates a pencil lead, a ballpoint cartridge or refill, etc.
Preferably in accordance with the invention it is provided that the shaft is of plastic material, preferably polypropylene, polyester, polyacrylate, polymethylmethacrylate, polycarbonate, polyamide, polyacetate, polyacetal, polystyrene and/or a combination of polystyrene with a polystyrene/butadiene copolymer. Out of the specified plastic materials, it is also possible for various types to be mixed or combined with each other, for example types involving different molecular chain lengths. The choice of the plastic material or the plastic material mix depends inter alia on whether it is to include the light-collecting substance and whether it is to come into contact with the writing substance. Thus for example polypropylene is admittedly not sufficiently transparent, but on the other hand it is best suited to forming the writing substance storage means, more specifically because of its best compatibility with all kinds of known writing substances, including water-based and alcohol-based writing materials.
As accordingly under some circumstances different plastic materials are to be provided on the one hand for receiving the light-collecting substance and on the other hand for forming the writing fluid storage means, it is particularly preferred in accordance with the invention for the shaft to be produced by co-extrusion of two or more plastic materials. That means that various regions of the shaft (for example a region with the light-collecting substance and another region for forming the storage means for the writing substance) do not have to be produced separately and then assembled by adhesive or the like. If different plastic materials are co-extruded, they should have comparable melting ranges and comparable shrinkage characteristics.